Recent developments in the roofing field have led to the making of synthetic shingles and tiles that simulate natural materials, for example, slate.
Such shingle or tiles can be manufactured with recesses, lines, grooves and seemingly random appearances, to yield aesthetically pleasing surface and edge characteristics, enhancing the ability of the synthetic shingles or tiles to appear to be natural materials.
Additionally, the benefits of making such synthetic shingles or tiles enable the cost-effective production of shingles or tiles, as well as producing shingles or tiles that generally are of less weight than comparable natural materials, in that they can be manufactured using different materials for a core, than the materials that are used on weather-exposed portions of the shingle or tiles when such shingles or tiles are installed on a roof. Such weather-exposed portions of the shingles or tiles can also have various desirable characteristics included in their manufacturing processes, such as algae-resistant qualities, flame retardant qualities, ultraviolet light resistant qualities, etc.
In general, when shingles or tiles are installed on a roof, they are laid up on a roof in courses, with their tab portions being weather-exposed, and the butt or headlap portions of the shingles or tiles being covered by shingles or tiles in a next-overlying course. Also, in applying shingles or tiles to a roof, the same are staggered laterally, so that lateral edges of shingles or tiles in an underlying course are not vertically aligned with lateral edges of shingles or tiles in a next-overlying course. At ends of courses of shingles or tiles it is usually necessary to cut the end-most shingles or tiles to size. Additionally, where there are intersecting surfaces of a roof, the shingles or tiles must generally be cut at an angle, for example, at the location of valleys where surfaces intersect, or for custom cuts in irregular areas, such as around vents, pipes, chimneys and other shapes.